Mechanical draft-fan.



F. NOLD & L. E. WILDQERMAN.

MECHANICAL DRAFT FAN.

APPLICATION FILED NOV. 6, 1911.

Patented Jan.7,1913.

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' Specification of Letters Patent. 'a neede auareve ber c, ie'u. seen no. 658,830.

Patented Jan. *1, 1913.

.To all whom it may concern:

Be it known that we, "Fnnnnnrox 'NoLn' and Loan: E. WHmnnMAN, citizens of" the United States, and residents-10f Frebiirg,

St. Clair county, Illinois, have invented certain new and useful Improvements m M'echanical'Draft-Fans, 0f which the follow ing is a specification containinga full, clear,.

and exact description, reference being had to the accompanying drawings, fornnng a part hereof. I

Our invention relates to improvements in mechanical draft fans, and the object of our invention is to construct a fan,.the construction of which reduces'thecost of such eculiar line 22 of Fig. 1 and in the direction indicated by the arrow.

Referring by numerals to the accompany-' ing drawings: 1 designates the base which supports the fan casing 2. The casing or stator 2 is preferably constructed, as shown, of sheet metal and is of the ordinary design having the in-take openings 3 in the side walls of the casin and the outlet 4:, the walls of which out et are tangential extensions of the casing 2.

5 designates the shaft upon which the rotor is mounted. This shaftis mounted in bearings, notshown, which are preferably independent of the casing or stator. The rotor comprises two spaced apart rings 6, the collars 7, the blades 8 and the blades 9. When the rotor is completely assembled and in position relative to the casing the rings 6 occupy positions within the casing and the collars 7 occupy positions outside of the casing.

Each. of the blades 8, which will be here:

'cured by rivets or bolts to the rings 6. The

blades 8 and flanges 10 are bent relative to radial lines through the rotor to present convexed'. surfaces for the expelling of air from the'casing. The body portions of each of the blades 8, that is the convexed surfaces as well :as the flanges 10 referred to,-donot extend the ,full. distance between the-inside and outside'margins of the rings 6. From the innermost end of the convexed or body portlon each of the blades 8 has "a forwardly mclined lane portion 11 which extend'sthe full widt between the-rings 6 and occupies a position at a tangent relative to'a'radial' hhe through the rotor. The blades 8 and rings 6 are connected withthe collars 7 by means of the blades 9, each of which blades i s taperedand their outermost margins have greater lengths than their innermost margins. Eah of the blades 9 is secured to the collars 7 by means of rivets or bolts 12 and at their outer ends each blade 9 is secured to the forwardly inclined portions 11 of the blades 8 by means of a strap 13 and to one .of the rings 6 by means of a stra 14. .The

forward margin of each of the lades 9 is held outside of the casing 2 and the rearmost margin of each blade 9 extends within the casing.

In the practical operation of our fan power is applied to the shaft-5 and the rotor set in motion and, when employed. as a draft fan, is rotated in the direction of the arrow A in-Fig. 1. The blades .8 serve to expel the air from the casing and thus produce a partial vacuum or suction which tends to draw the airthrough the in-take openings into the casing. The function or oiiice of the blades'9 is to reach out or exair toward the outer wall of the casing.

After the air passes over the inclined portions 11 it is received by the convexed body portions of the' blades 8 which convexity further serves to force the air toward the outer wall of the casing. In this manner the rotor, as a whole, has no portion whic might create a back pressure. Y

By the construction shown we are en abled to build practically the, entire rotor from sheet metal which materially lessens the cost of fan rotors.

We claim:

-1. In a mechanical draft fan, the combination with a casing of a rotor comprising radial blades which extend transversely of the casing, each blade having a forwardly inclined inner end and blades which extend from the first mentioned blades to a point adjacent the axis of the rotor, the forward margins of which last mentioned blades extend outside of the casing and their inner margins extend to points within the casing, the outermost ends of said blades approximately paralleling said radial blades and the innermost ends disposed at approximatel right angles to the outermost ends.

2. 121 a mechanical draft fan, the combination with a casing having intake openings in its side walls and a perlpheral outlet, of a rotor comprising blades extending transversely relative to the casing and radially relative to the rotor, and a set of blades adjaoent each intake opening, each blade of which is located wholly within the casing at its outer end and extended outside the easing at its inner end, the outer end of each of said blades being substantially at right' an les relative to the inner end, said outer ;necting said rings, and a plurality of blades arranged between and connected with said rings and collars, the innermost ends of said last mentioned blades being substantially parallel with said collars and the outermostends of said last mentioned blades being substantially parallel with the first mentioned blades. I

In testimony whereof, we have signed our names to this specification, in presence of two subscribing witnesses.

FREDERICK NOLD. LOREN E. WILDERMAN.

. Witnesses:

E. L. WALLACE, E. LONGAN. 

